Research in our current cross-sectional study of language in normal and demented elderly subjects documents certain age-related changes in linguistic skills and strategies. Moreover, evidence from both polyglot and monolingual aphasics suggests that the anatomical substrate for language may change with aging. The proposed research extends the present study in a longitudinal format. Focus will be on four linguistic phenomena related to aging: naming difficulty, disorders of comprehension, change in discourse style, and change in cerebral lateralization for language. Ninety subjects (30 demented and 60 healthy) will be tested three times over the three years of the project. Each year the subject will be tested by 1) a clinical neurological and neurobehavioral assessment, 2) a dementia screening test developed previously for use in a large-scale epidemiological study, 3) an audiometric test and 4) the series of four psycholinguistic tests described in this proposal. In order to document changes in language behavior in the elderly, and to test possible neuroanatomical changes which may underlie them, we will refine two clinical "bedside" tests (i.e. naming; and evaluation of spontaneous speech) and employ two experimental procedures which necessitate instrumentation (Carousel projector for the lateralization measure, videotape for the comprehension battery). Quantitative and qualitative analyses will be performed on the data of each test, and cross sectional as well as longitudinal comparisons will be made. The projected research should suggest strategies to aid impaired (e.g. hard of hearing or anomic) elderly, and perhaps also dementing individuals. In addition, we hope to discover a simple linguistic test to identify dementing patients, so that corrective measures might be taken at an early stage in the process.